Abstract Nipah (NiV) has been recognized as both an important bioterror risk and a global health risk with broad, unpredictable pandemic potential. Infection from this paramyxovirus is devastating, rapidly causing lethal encephalitis and serious respiratory infections. Transmitted by air or food, its mechanism of infection is complex, and no drugs exist to prevent or treat it. Recently, we have successfully prevented and treated NiV infection in golden hamsters. Key to this success is the surprising finding from our biodistribution studies, that a single subcutaneous injection of the peptide generates sufficient antiviral concentrations for effectiveness in the lung, endothelium and, most importantly, in the brain, the organs targeted by NiV infection, without any toxic effect. We plan to use this information to develop highly effective fusion-inhibitory antivirals for henipaviruses; to determine the optimal dose regimens for CNS localization of cholesterol-conjugated peptides; to investigate the mechanisms of resistance to fusion inhibitors; and to test these hypotheses in animal models of NiV disease. We will apply the results of our fundamental research in chemistry, bioengineering and virology to the development of a new broad-spectrum antiviral strategy based on inhibiting virus entry systemically as well as in the central nervous system (CNS). By utilizing these innovative approaches and technologies, we will determine the feasibility of developing CNS-targeted fusion inhibitors for human use, and also set the stage for a platform technology applicable to other paramyxoviruses and for the treatment of other acute viral encephalitides. 1